Problem: Vanessa has taken 6 exams and her average score so far is 85. If she gets 100, a perfect score, on the remaining 4 exams, what will her new average be?
If she gets 100 on the remaining exams, the sum of her scores will be $6 \cdot 85 + 4 \cdot 100 = 910$ Her overall average will then be $910 \div 10 = 91$.